The present invention relates generally to pharmaceutical products and methods and, more specifically, to methods and compositions useful for diagnosing scurfy-related diseases, as well as methods for identifying compounds which can modulate the immune system.
Inherited mutations affecting the murine immune system have proven to be a rich source of novel genes critical to the regulation of the immune system and have furnished important animal models for human immunological disorders. These include xid, the murine equivalent of X-linked agammaglobulinemia (Thomas et al., Science 261:355, 1993; Rawlings et al., Science 261:358, 1993), beige (the equivalent of Chediak-Higashi Syndrome) (Barbosa, et al., Nature 382:262, 1996), lpr and gld (defects in fas and fas-ligand), X-linked severe combined immunodeficiency (Sugamura et al., Annu. Rev. Immunol. 14:179, 1996), and the hematopoietic cell phosphatase mutant motheaten (SHP-1) (Bignon and Siminovitch, Clin Immunol Immunopathol 73:168, 1994).
One mouse mutant of particular interest is the as-yet uncloned X-linked mouse mutant, scurfy (sf). Briefly, mice hemizygous for the scurfy mutation exhibit a severe lymphoproliferative disorder. In particular, males hemizygous (Xsf/Y) for the scurfy mutation develop a progressive lymphocytic infiltration of the lymph nodes. spleen, liver and skin resulting in gross morphological symptoms which include splenomegaly, hepatomegaly, greatly enlarged lymph nodes, runting, exfoliative dermatitis, and thickened malformed ears (Godfrey et al., Amer. J. Pathol. 138:1379, 1991; Godfrey et al., Proc. Natl. Acad. Sci. USA 88:5528, 1991). Other clinical symptoms include elevated leukocyte counts, hypergammaglobulinemia, and severe anemia (Lyon et al., Proc. Natl. Acad Sci. USA 87:2433, 1990); the death of affected males usually occurs by 3 weeks of age. The sf locus has been mapped to the extreme proximal region of the X chromosome, approximately 0.7 centimorgans from the locus for sparse-fur (spf) (Lyon et al., Proc. Natl. Acad Sci. USA 87:2433, 1990; Blair et al., Mamm. Genome 5:652, 1994), itself a point mutation within the ornithine transcarbamylase gene (Otc) (Veres et al., Science 237:415, 1987). The sf locus is also tightly linked to the murine Gata1, Tcfe3, and Wasp loci (Blair et al., Mamm. Genome 5:652, 1994; Derry et al., Genomics 29:471, 1995). Similarities between scurfy and human Wiskott-Aldrich syndrome (WAS) have been noted (Lyon et al., Proc. Natl. Acad Sci. USA 87:2433, 1990), and the mouse Wasp gene has been proposed as a candidate for scurfy (Lyon et al., Proc. Natl. Acad Sci. USA 87:2433, 1990; Derry et al., Genomics 29:471, 1995). Closer biological examination reveals significant differences between WAS and scurfy, however, and the two loci have been demonstrated to be non-allelic (Jeffery and Brunkow, unpublished data). Thus, prior to applicants"" invention the identity of the scurry gene remained to be determined.
The present invention discloses methods and compositions useful for diagnosing scurfy-related diseases, as well as methods for identifying compounds which can modulate the immune system, and further provides other related advantages.
The present invention relates generally to the discovery of novel genes which, when mutated, results in a profound lymphoproliferative disorder. In particular, a mutant mouse, designated xe2x80x98Scurfyxe2x80x99, was used to identify the gene responsible for this disorder through backcross analysis, physical mapping and large-scale DNA sequencing. Analysis of the sequence of this gene indicated that it belongs to a family of related genes, all containing a winged-helix DNA binding domain.
Thus, within one aspect of the invention isolated nucleic acid molecules are provided which encode FKHsf or Fkhsf, including mutant forms thereof. Within certain embodiments, Fkhsf of any type may be from a warm-blooded animal, such as a mouse or human. Within further embodiments, isolated nucleic acid molecules are provided wherein the nucleic acid molecule is selected from the group consisting of (a) a nucleic acid molecule that encodes an amino acid sequence comprising SEQ ID Nos 2, or, 4, (b) a nucleic acid molecule that hybridizes under stringent conditions to a nucleic acid molecule having the nucleotide sequence of SEQ ID Nos: 1, or, 3, or its complement, and (c) a nucleic acid molecule that encodes a functional fragment of the polypeptide encoded by either (a) or (b). Preferably, the nucleic acid molecule is not JM2. Within related aspects, vectors (including expression vectors), and recombinant host cells are also provided, as well as proteins which are encoded by the above-noted nucleic acid molecules. Further, fusion proteins are also provided which combine at least a portion of the above-described nucleic acid molecules with the coding region of another protein. Also provided are oligonucleotide fragments (including probes and primers) which are based upon the above sequence. Such fragments are at least 8, 10, 12, 15, 20, or 25 nucleotides in length, and may extend up to 100, 200, 500, 1000, 1500, or, 2000 nucleotides in length.
Within other aspects methods of using the above noted expression -vector for producing a Fkhsf protein (of any type) are provided, comprising the general steps of (a) culturing recombinant host cells that comprise the expression vector and that produce Fkhsf protein, and (b) isolating protein from the cultured recombinant host cells.
Also provided are antibodies and antibody fragments that specifically bind to Fkhsf proteins. Representative examples of such antibodies include both polyclonal and monoclonal antibodies (whether obtained from a murine hybridoma, or derived into human form). Repesentative examples of antibody fragments include F(abxe2x80x2)2, F(ab)2, Fabxe2x80x2, Fab, Fv, sFv, and minimal recognition units or complementarity determining regions.
Within yet other aspects, methods are provided for detecting the presence of a Fkhsf nucleic acid sequence in a biological sample from a subject, comprising the steps of (a) contacting a Fkhsf specific nucleic acid probe under hybridizing conditions with either (i) test nucleic acid molecules isolated from said biological sample, or (ii) nucleic acid molecules synthesized from RNA molecules, wherein said probe recognizes at least a portion of nucleotide sequence of claim 1, and (b) detecting the formation of hybrids of said nucleic acid probe and (i) or (ii).
Within another related embodiment, methods are provided for detecting the presence of an Fkhsf, or a mutant form, thereof, in a biological sample, comprising the steps of: (a) contacting a biological sample with an anti-Fkhsf antibody or an antibody fragment, wherein said contacting is performed under conditions that allow the binding of said antibody or antibody fragment to said biological sample, and (b) detecting any of said bound antibody or bound antibody fragment.
Within other aspects of the invention, methods are provided for introducing Fkhsf nucleic acid molecules to an animal, comprising the step of administering a Fkhsf nucleic acid molecule as described herein to an animal (e.g., a human, monkey, dog, cat, rat, or, mouse. Within one embodiment, the nucleic acid molecule is contained within and expressed by a viral vector (e.g., a vector generated at least in part from a retrovirus, adenovirus, adeno-associated virus, herpes virus, or, alphavirus). Within another embodiment the nucleic acid molecule is expressed by, or contained within a plasmid vector. Such vectors may be administered either in vivo, or ex vivo (e.g., to hematopoietic cells such as T cells.
Within other embodiments, transgenic non-human animals are provided wherein the cells of the animal express a transgene that contains a sequence encoding Fkhsf protein.